Electric meter



(No Model.) 7

- M. M. M SLATTERY.

ELEGTBIG METER.

No. 410,860. Patented Sept. 10; 188-9.

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UNITED STATES PATENT OFFICE.

MARMADUKE M. M. SLATTERY, OF FORT IVAYNE, INDIANA.

I ELECTRIC METER.

SPECIFICATION forming part of Letters Patent No. 410,860, datedSeptember 10, 1889.

Application filed May 17, 1889- Serial No. 311,116. (No model.)

.To all whom it may concern.-

Be it known that I, MAEMADUKE M. M. SLATTERY, a citizen of the UnitedStates, residing at Fort WVayne, in the county of Allen, in the State ofIndiana, have invented certain new and useful Improvements in ElectricMeters; and I do hereby declare that the following is a f ull,clear, andexact description of the invention,which will enable others skilled inthe art to which it appertains to make and use the same, reference beinghad to the accompanying drawing, which forms part of this specification.

My invention relates more especially to the fans, vanes, or similarretarding devices which arefrequently used in meters for measuring andindicating, by means of a motor operated or controlled by the currentand suitable mechanism in connection therewith, the quantity of electriccurrent which may have passed through such meter in a given time. In theabsence of any provision to the contrary it is a generally-accepted lawthat the speed of rotation of such a motor will increase approximatelyas the square of the current applied to it, and it is also recognized astrue that the retarding effect of a revolving fan or vane, due to theatmospheric pressure thereon, varies approximately as the square of thespeed of rotation. Theoretically, therefore, the application of such aretarding device to such a motor should result in indications of theregistering mechanism proportional to the current passing; and this isin fact true in practice with approximate accuracy within acomparatively-narrow Working range; but it is found in practice that asbetween a Very light and a very heavy load this proportionality does notalways obtain, and that the retarding effect is in such case greater athigh speed than it ought to be.

To obviate this irregularity is the purpose of my present invention, andthis I do by giving to the blades of the retarding device a variablesurface exposed to the pressure of the air, and consequently a variableresistance to revolution. This I accomplish by dividing the fan into twoor more portions, one fixed to the rotating shaft and the others pivotedin a plane or planes parallel to the first,

so as at high speed to be thrown outward by the centrifugal force oftheir own revolution. The parts are thus folded together, one partsliding over an other, in the manner of a slideshutter, so reducing thearea exposed to atmospheric pressure.

In the drawing, A is a general view of a form of meter described by mein other patents and applications for patents, and not hereinspecifically claimed.

B is the rotating shaft pivoted at C. I) D are vanes or fan-bladesattached thereto and revolving therewith. These are preferably of asectoral or quadrant form, and disposed as shown.

At E E are pivoted other portions of the blades or fans, which may be ofsimilar form, and constitute with the fixed portions, when at rest orrevolving very slowly, one complete blade of semicircular form, or ofthe form of a larger sector of a circle. Attached to these movableportions as counter-balances are small weights F F, which mayconveniently be made adjustable on the light shafts or rods G G,connecting the same to the movable portions at the pivot. Thisadditional weight to assist inertia may be disposed within or upon themovable blade or fan itself; but the form shown is preferred as beingefficient and convenient. When the speed of rotation of the fanincreases beyond a certain velocity,

its movable portion is thrown outward by centrifugal force and folds orslides over the rigid portion, thus reducing the area exposed andreducing the resistance offered to the revolution of the fan by theatmosphere.

I claim-- 1. In combination with an electric meter, a retarding deviceconsisting of a folding fan presenting a variable surface to theatmosphere.

2. In combination with an electric meter, a retarding device consistingof afan revolving in the atmosphere and folding upon itself by theaction of centrifugal force.

3. In an electric meter, a retarding device consisting of a folding fanrevolving in the atmosphere, with an adjustable weight attached to itsmovable portion.

4. In an electric-motor meter, a retarding device consisting of a fan1'e\"0lving against atmospheric pressure and having one portionfixedrigidly to the motor-shaft, with a mova ble portion or portionsadapted to slide over the fixed portion by the action of centrifugalforce at high velocity, and so reduce the area exposed to atmosphericpressure.

5. In an electric meter, a retarding device eonsistingof arevolving fandivided into seetions adapted to slide together at high ve 1o locity.

In testimony whereof I do hereto subscribe my name, in the presence oftwo witnesses, this 15th day of May, 1889.

MAKMADUKE M. M. SLA'LTEILY.

\Vitnesses:

OHAs. C. .MILLER, J. E. TALBOT.

